If neither barrel will fire, it is probably a broken striker. That gun has a hammer that is a sort of hollow shell and inside is a pivoting striker that is cammed up to fire the top barrel and let down to fire the lower, depending on the position of a cam wheel that is indexed when the hammer is cocked by the trigger. The gun is not extremely difficult to work on but I agree on the white towel and magnet. Make sure you take the tension off the mainspring and remove it before trying to dissassemble the rest of the gun.